Body side spray machine



Nov. 14, 1961 w, R JR, ET AL 3,008,648

BODY SIDE SPRAY MACHINE Filed April 25, 1960 4 Sheets-Sheet 3 INVENTORI AT-TORNEY Nov. 14, 1961 w. A. BRADY, JR., ET AL ,6

BODY SIDE SPRAY MACHINE 4 Sheets$heet 4 Filed April 25, 1960 IN VENTORJ' ATTORNEY nite States Patent Ofiicc 3,008,648 Patented Nov. 14, 1961 3,008,648 BQDY SlDE SPRAY MAC William A. Brady, Jr., Warren, and Joseph R. Tolstyka,

Detroit, Mich, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Apr. 25, 1960, Ser. No. 24,441 Claims. (Cl. 239-186) This invention relates to paint spray equipment and more particularly to an automobile body side paint spray machine.

In the automobile industry automobile bodies are spray painted on a conveyor line and the rate of travel of the conveyor is limited by the speed at which the painting operation can be accomplished. Presently the most common method of painting automobile body sides is to pass a spray nozzle along the body side in a vertical reciprocatory path. The speed at which the vehicle body on the conveyor line can be moved is a direct function of the number of reciprocations of the spray nozzle per minute; hence, the faster the spray nozzle is reciprocated the greater will be the area of the car body sprayed in a given time. If the speed of the travel of the spray nozzle vertically along the body side can be increased then the speed of the conveyor in a horizontal direction can also be increased; and consequently, the spraying operation will take a considerably lesser time. Some of the limitations on increased speed of the spray painting operation are uniformity of the paint spray and the rigidity of the paint spray nozzle carrying apparatus while being translated. In order to obtain desired rigidity of the spray nozzle during its movement along the surface to be sprayed, previous devices have utilized cumbersome com- 7 plicated carriage mechanisms which are rigidly guided in trackways consisting of rods, slides, slots and similar devices. During a paint spraying operation a certain amount of the paint spray circulates back onto the paint spray equipment and is deposited thereon so that one of the operative problems of paint spray equipment is the failure of nozzle carriages due to accumulation of paint spray on the carriage and the associated guide Ways. Belt type carriages are pmicularly vulnerable to over spray failures.

This invention provides a new paint spray machine that is capable of carrying a spray nozz'le at approximately twice the speed of present apparatus and which is provided with carriage mechanism that is virtually selfcleaning to eliminate failure of the spray apparatus due to accumulation of'paint on the carriage device. While the invention was designed for use in the painting of automobile bodies it may be embodied in machines for other uses.

Some of the objects of this invention are to provide a paint spray machine that-is capable of carrying a spray nozzle along a surface to be painted at a rate of travel greatly exceeding the capabilities of previous apparatus; to provide nozzle carriage mechanism that substantially eliminates maintenance problems caused by the accumulation of paint on the apparatus during the spraying operation; to provide a machine of comparative simplicity having no appreciable wearing problems and capable of high volume usewithout maintenance; and to provide auto.- matic machinery capable of faster spraying without loss of product uniformity.

To accomplish the aforementioned objects a pair of parallel driven chain members supported on spaced sprocket wheels and extending the length of the body to be sprayed are provided. A spray nozzle is linked directly to each of the driven chains and the paint spray orifice isspaced outwardly therefrom to. be positioned Qlosely adjacent the body to be sprayed. A drivechain is pivotal,- ly linked to one of the driven chains andis spaced adjacent thereto so that endlms movement of the drive chain caused by a power source imparts a reciprocatory movement to the spray nozzle on the driven chains which have rapid limited reversing movement. Thus the driven chains have limited vertical movement about their sprocket supports while the drive chain travels in an endless path around its sprocket supports. The driven chains support the spray nozzle with suflicient rigidity to obtain a satisfactorily uniform spray on the body to be painted and the chain members are reversely movable about their sprockets at unexpectedly high rates of speed without undesirable wobble being imparted to the spray nozzle. Furthermore, the chain members and sprockets comprise the only nozzle carrying means, and excess paint spray does not accumulate on their surfaces due to the lubricant thereon and the coaction thereof; and, in fact, the rapid movement of the chain members makes the whole mechanism selfcleaning. Although some similarity may be suggested between my device and prior devices which have a spray nozzle carried in an eliptioal path by an endless member or to a spray nozzle carried in a reciprocatory path by an endless member, one skilled in the art will readily comprehend that the unique features of this invention overcome the limitations of the prior art devices.

Other objects and advantages will become apparent from the following detailed description in which reference is made to the accompanying drawing wherein:

FIGURE, 1 is a perspective View of the preferred embodiment of this invention;

FIGURE 2 is a side elevational view of a portion of the apparatus shown in FIGURE 1 with parts broken away;

FIGURE 2a is a side elevational view of another portion of the apparatus shown in FIGURE 1;

FIGURE 3 is an end view taken along the line 33 in FIGURE 2; and,

FIGURE 4 is a detail View taken along the line 4-4 in FIGURE 2a.

Referring now to FIGURE 1 a paint spray machine comprising a frame having a base portion 10, upwardly extending support pillars 12, 13 and support plates 14, 15 is enclosed by a three-sided safety cage 16. A conventional electric motor and an integral variable speed clutch combination 17 is mounted on the machine base 10 and includes a suitable speed-control device 18. A lower drive sprocket wheel 19 is rotatably secured to a drive shaft 20 of the motor combination 17 and an upper sprocket wheel 21 is rotatably cooperable with an idler pin 22 supported in a bearing member 24 that is attached tothe support plate 15.

A drive chain 25 is supported on the sprocket wheels 1?, 2.1- and rotatable therearound in an endless path defined by substantially linear translation between the axes of rotation of the sprocket wheels and curvilinear paths therearound. A connecting block 26 is mounted on the chain member 25 and pivotally supports ashaft extension 27 shown in FIGURE 2a.

A pair of driven chains 28, 29 are parallelly mounted on lower sprocket wheels, 30, 31 and upper sprocket wheels 32, 33. that are rotatably supported in, bearing members 35', 36 vertically spaced and supported on the pillar 12; The upper sprocket wheels 32, 33 are secured to an upper sprocket idler shaft 38 and the lower sprocket members are secured to a, lower sprocket idler shaft 39 so that the sprocket wheels 30,31, 32, 33 have identical rotative movement about parallel vertically spaced axes. A second connecting block 40; is, secured, to and carried by one of the, driven chains 28 and provided with, a pivotally supported shaft extension 41. A connecting arm 42. is pivotally secured at opposite ends to the shaft, extensions 27 and, 41L It is to. be noted that the vertical distance between the rotative axes of the upper and lower sprockets of the driven chains is somewhat greater than the vertical distance between the rotative axes of the drive chain sprockets and, further, that the rotative axes of the drive chain and the driven chains are vertically ofiset. The vertical distance between the shaft extensions 27, 41 is maintained slightly less than the distance that the upper sprockets of the driven chains are vertically offset from the upper sprocket of the drive chain by having the connecting arm 42 of a suitable length as shown in FIGURE 4. Thus the connecting block on the driven chain 23 is confined to a reciprocatory path between the axes of the upper sprockets and lower sprockets of the driven chains.

A paint spray gun 44 having conventional air and paint hose connections is reciprocably carried on the driven chains by a connecting link 45 pivotally secured to connecting blocks 46, 47 mounted on the driven chains by links 48, 49 at points on the driven chains oppositely spaced from the connecting block 40 so that the spray gun is reciprocated in a vertical path only and has no motion around the upper and lower sprockets. The orifice of the spray nozzle 44 is substantially parallel to the rotative axes of the driven sprocket wheels and is adjustable between fore and aft spray positions determined by engagement of limit pins 50 and 51 carried by an extension 52 of the link 49 with a limit block 53 formed on the connecting block 47. The spray nozzle is maintained in the selected position by the force exerted by a tension spring 54 fixed between the limit block and a pin 55 on the connecting link 45. An air operated servomotor 56 is suitably secured adjacent the driven chains and actuates a rod 57 extending through a bushing 58 fixed to the link 45 and through a slot 79 in a support plate 77 to position the nozzle in cooperation with the spring 54. The air motor is connected in a conventional manner to a high pressure source, and the rod 57 is suitably fastened to the support pillar 12 above the uppermost point of the reciprocatory path of the link 45 to permit adjustment in all positions.

Paint spray control apparatus is provided to shut off the paint spray during certain periods of the spray process and comprises rotary timer mechanism 59 secured to the support pillar 13 by the support plates 14, 15 and driven through a chain 60 and sprocket wheel 62 secured to the other end of the idler pin 22. The chain 60 drives the sprocket wheel 61 and a rotatable shaft 63 to which is fixed a sprocket wheel 64 to drive a second rotatable shaft 65 through a chain 66 and sprocket wheel 67. Cam sets 68, 69 are provided on the shafts 63, 65 to actuate air valves 70 through cam followers 71, 72 carried by a pivotally supported link 74 to shut off the paint spray when the drive link 26 is being rotated around the upper and lower sprocket wheels 19, 21 and the nozzle dwells on the driven chains. An air cylinder 75 is actuable to move the cam followers 71, 72 from one set of earns 68 to the other set of cams 69 to provide multiple spraying patterns. It is to be understood that suitable chain Inbricant is applied to the chains and the sprocket wheels so that a minimum of wear occurs between the chains and the sprocket wheels. Chain support plates 76, 78 are provided with chain engaging runners 80, 82 of nylon or other suitable wear resistant plastic material and are fixed to the support pillar 12 by brackets 81, 86. Adjusting screws 88, are provided to suitably tension the driven chains 28, 29 by sliding the chain support plates outwardly against the chains on support pins 92, 94.

In operation the electric motor is driven by the motor combination 17 which drives the sprocket wheel 19 at an rpm. selectively adjustable through the speed control device 18. The drive sprocket 19 drives the drive chain 25 around the upper sprocket wheel 21 in an endless path and carries the connecting link 26 in that path. The connecting arm 42 is carried by the connecting link 26, which in turn, drives the rotative axes connecting block 40 in a reciprocatory path between the rotative axes of the upper and lower sprocket wheels 30, 31 and 32, 33. It will be seen in FIGURE 4 that no motion will be transferred from the drive chain 25 through the connecting arm 42 to the driven chains 28, 29 when the connecting block 26 is rotatably carried around the upper and lower sprocket wheels 19, 21 because of the spacing of the parts. The curvilinear motion of the connecting block 26 will be accommodated by the pivotal connections between the connecting blocks '26, 40 and the connecting arm 42 so that a dwell period will exist for the spray nozzle during reversal of direction of movement. In order to control the paint spray during dwell periods and other times, the cam timing mechanism is provided to actuate the control valves 70. The driven chains 28, 2.9- will be reversibly driven through a distance approximately equal to the distance of the linear path of travel of the connecting block 26 on the drive chain 25 as the connecting link 26 travels upwardly in a linear path and then downwardly in a linear path. The result will be a reciprocable motion of the spray nozzle between the upper and lower sprocket wheels 32, 33 with harmonic acceleration and deceleration as the connecting block 26 passes around the sprocket wheels 19, 21. Nylon surfaced backing plates may be positioned behind the driven chain members 28, 29 to more rigidly support them and prevent excessive wobble transverse to their axes of rotation. The nylon surfaced backing plates wear exceedingly well and combined with the normal heavily lubricated condition of the chain members present no maintenance problems whatsoever even after thousands of hours of use. The excess spray of the spray nozzle does not accumulate on the chains or sprockets because of the rapid reversing action of the sprockets on the chains and because of the relatively heavy lubricant carried by. the chains and sprockets, and therefore, the spray nozzle reciprocating mechanism exposed to excessive paint spray is selfcleaning and the machine may be run for extremely large production with no down time for maintenance repairs due to accumulation of paint on the machine surfaces. The position of the spray nozzle may be varied relative to the work piece by actuation of the air motor 56 to move the support link 45 over center about the pivotal links 48, 49 whereat that the spring 54 and the stop pins 50, 51 are efliective to rigidly position the nozzle. It is to be also noted that the particular link structure between the drive chain and the driven chain provides for harmonic deceleration and acceleration which is particularly well suited to my chain driving mechanism. Furthermore, the sprockets and the chain maintain a positive driving connection between the power source and the spray nozzle at all times and no trackway is required to guide the spray nozzle itself.

It should, therefore, be apparent that the illustrated paint spray machine is of comparative simplicity requiring little maintenance and is adaptable to a wide variety of uses requiring rapid reciprocation of the spray nozzle along a surface to be painted. It is also apparent that some modifications are possible without departing from the spirit and scope of this invention as defined by the appended claims.

The invention claimed is:

1. Paint spray apparatus comprising a frame, a power source provided on said frame, control means associated with said power source, a pair of spaced idler shafts parallelly mounted on said frame, a pair of spaced sprocket Wheels mounted on each idler shaft and each of said pair of spaced sprocket wheels on each idler shaft being aligned for rotative movement in a common parallel plan with one another on said idler shafts, a plurality of parallelly mounted chain members rotatably supported on said sprocket wheels and, a spray nozzle support fixedly secured to each of said chain members and being movable therewith, a spray nozzle carried by said spray nozzle support, drive mechanism interconnect ing said power source and said chain members, and said drive mechanism being connected to said chain members through motion limiting means to restrict movement of said nozzle to a reciprocatory path between said sprocket wheel means.

2. Paint spray apparatus comprising a frame, a power source, and control means for said power source, a pair of spaced parallel idler shafts mounted on said frame, a first set of sprocket wheel means mounted in parallel alignment on said idler shafts, a second set of sprocket wheel means mounted in parallel alignment on said idler shafts and being spaced from said first set of sprocket Wheel means along said idler shaft, a plurality of parallelly mounted chain members rotatably mounted on said sprocket wheel means, a spray nozzle support fixedly secured to each of said chain members and being movable therewith, a spray nozzle mounted on said spray nozzle support drive mechanism interconnecting said power source and said chain members, said drive mechanism being connected to said chain members through motion limiting means to restrict movement of said nozzle to a reciprocatory path between said sprocket wheel means, and power actuable means to variably position said nozzle relative to said chains.

3. Paint spray apparatus comprising a frame, a power source mounted on said frame, control means for said power source, a pair of spaced idler shafts parallelly mounted on said frame, a plurality of sprocket wheel means mounted on said idlers shafts, said sprocket wheel means being spaced from one another on each of said idler shafts and being correspondingly spaced and aligned on each of said idler shafts to form a plurality of rotative sets a plurality of parallelly mounted chain members, rotatively supported on said rotative sets of sprocket wheel means a spray nozzle support, pivotal links interconnecting said nozzle support and said chain members, a spray nozzle supported and carried by said spray nozzle support, a servomotor secured to said frame, control means actuable by said servomotor and operatively associated with said pivotal links to variably position said spray nozzle relative to said chain members, spring means associated with said support to maintain said spray nozzle in a selected position, said pivotal links being fixedly secured to each of said chain members and being movable therewith, drive mechanism interconnecting said power source and said chain members, and said drive mechanism being connected to said chain members through motion limiting means to restrict movement of said nozzle to a reciprocatory path between said sprocket wheel means.

4. Paint spray apparatus comprising a frame, a power source mounted on said frame, control means for said power source, a pair of parallel spaced idler shafts mounted on said frame, an endless carrying member rotatably mounted on said idler shafts, a spray nozzle connected to said endless carrier member and being movable therewith, drive mechanism interconnecting said power source and said endless carrier member, said drive mechanism being connected to said endless carrier member through motion limiting means to restrict movement of said nozzle to a reciprocatory path between said spaced idler shafts, timing mechanism drive means operably connected to said drive mechanism, a plurality of shafts rotatably driven by said drive means, cam means mounted on said shafts, a spray control valve, a valve control link pivotally supported on said frame adjacent said shaft, cam follower means operatively connected to said link and actuab-ly engaged with said cam means to disrupt the spraying operation during predetermined portions of nozzle movement.

5. Paint spray apparatus comprising a frame, a power source mounted on said frame, control means for said power source, a pair of spaced idler shafts parallelly mounted on said frame, a plurality of sprocket wheel means mounted on said idler shafts, said sprocket wheel means being spaced from one another on each of said idler shafts and being correspondingly spaced and aligned on each of said idler shafts to form a plurality of rotative sets, a plurality of parallelly mounted chain members rotatively supported on the rotative sets of said sprocket wheel means, a spray nozzle support fixedly secured to each of said chain members and being movable therewith, a spray nozzle mounted on said support, chain support brackets fixed to said frame between said chain members, support arms extending outwardly from said brackets and positioned inside of each of said chain members, plastic runners fixed to said support arms and being engageable with the nozzle carrying portion of each of said chain members throughout the reciprocatory path of said nozzle, drive mechanism interconnecting said power source and said chain members, and said drive mechanism being connected to said chain members through motion limiting means to restrict movement of said nozzle to a reciprocatory path between said sprocket wheel means.

6. Paint spray apparatus comprising a frame, a power source mounted on said frame, control means for said power source, a pair of spaced idler shafts parallelly mounted on said frame, a plurality of sprocket wheel means mounted on said idler shafts, said sprocket wheel means being spaced from one another on each of said idler shafts and being correspondingly spaced and aligned on each of said idler shafts to form a plurality of rotative sets, a plurality of parallelly mounted chain members rotatively supported on the rotative sets of said sprocket wheel means, a spray nozzle support fixedly secured to each of said chain members and being movable therewith, a spray nozzle mounted on said support, chain support brackets fixed to said frame between said chain members, support arms extending outwardly from said brackets and positioned inside of each of said chain members, plastic runners fixed to said support arm-s and being engageable with the nozzle carrying portion of each of said chain members throughout the reciprocatory path of said nozzle, adjustable means associated with said plastic runners for variable positioning thereof outwardly against said chain members, drive mechanism interconnecting said power source and said chain members, and said drive mechanism being connected to said chain members through motion limiting means to restrict movement of said nozzle to a reciprocatory path between said sprocket wheel means.

7 A spray mechanism having a base and a support pillar and comprising a motor, a drive shaft rotatably supported by said motor, a first sprocket wheel associated with said shaft for rotation about a first axis of rotation parallel to said base section, bearing means fixed to said support pillar and rotatably supporting a first idler shaft, -a second sprocket wheel associated with said first shaft for rotation about a second axis of rotation parallel to said first axis of rotation and vertically spaced from and aligned therewith, a drive chain rotatably supported on said first and second sprocket wheels and translatable therearound in an endless path, a pivotal connecting member carried by said drive chain, a second bearing member supported by said support pillar and rotatably supporting a second idler shaft, third and fourth sprocket wheels horizontally spaced from one another and said first sprocket wheel and associated with said second shaft for rotation about a third axis of rotation parallel to said first axis of rotation and vertically spaced a distance thereabove, a third bearing member supported by said support pillar and rotatably supporting the third idler shaft, fifth and sixth sprockets vertically and horizontally aligned with said third and fourth sprocket wheels and associated with said third idler shaft for rotation about a fourth axis of rotation vertically spaced above said second axis of rotation a distance equal to the spaced distance between said first and third axis of rotation, driven chain member rotatably supported on said third and fifth sprockets and said fourth and sixth sprockets, and translatable in a path therearound, a pivotal connecting member carried by one of said driven chains, a connecting rod pivotally connnecting said connecting members and vertically displacing said members a distance less than the distance between said upper axes of rotation of said driven chain and said upper axes of rotation of said drive chain whereby said second pivotal member will be re ciprocated on said chain betweeen the upper and lower axes of rotation of said driven chain, a spray nozzle support bar pivotally connected to each of said driven chains, a spray nozzle carried by said support bar and having an orifice parallel to said axis of rotation and horizontally spaced away from said motor beyond said driven chains and means to limit pivotal movement of said support on said driven chain to a first and second position representing a maximum outward position and a maximum inward position of said spray nozzle.

8. A side paint spray machine comprising a frame having a base portion and an upstanding pillar portion, a power source secured to the base of said frame, a drive sprocket rotatably driven by said power source about an axis of rotation parallel to said base portion, a driven sprocket supported on said pillar portion is vertical alignment with said drive sprocket and rotatable about an axis parallel to said rotative axis of said drive sprocket, a chain rotatably supported on said drive sprocket and said driven sprocket and translatable in an endless path around said rotative axes, a drive arm pivotally connected to said drive chain and movable therewith throughout the endless path thereof, a plurality of driven chain members rotatably supported on said pillar about rotative axes axes parallel to said base portion, means pivotally connecting said drive arm to one of said driven chain members at a point located between the rotative axes of said driven chain members, a spray nozzle having an orifice parallel to the axis of rotation of said driven chain members and spaced axially outwardly of said driven chain members, a support carrying said nozzle and fastened to said driven chain members between their rotative axis, and means to limit movement of said nozzle on said driven chain members to a reciprocatory path between the rotative axes thereof.

9. The paint spray machine as defined in claim 8 and having pivotal links interconnecting said support for said nozzle and said driven chain members, a servomotor secured to said frame, control means actuable by said servomotor and operatively associated with said pivotal links to variably position said spray nozzle relative to said driven chain members, holding means associated with said support to maintain said spray nozzle in a selected position, and said pivotal links being secured to each of said driven chain members for movement therewith in said selected position.

10. The side paint spray machine as defined in claim 8 and having timing mechanism drive means operably connected to said power source and driven in timed relationship to said drive sprocket, a plurality of shafts rotatably driven by said drive means, cam means mounted on said shafts, a spray control valve, a valve control link pivotally supported on said frame adjacent said shafts, cam follower means operatively connected to said link and actuably engaged with said cam means to disrupt the spraying operation during predetermined portions of nozzle movement.

11. The paint spray machine as defined in claim 8 and having chain support brackets fixed to said frame between said driven chain members, support arms extending outwardly from said brackets and positioned inside of each of said driven chain members, back-up runners fixed to said support arms and being engageable with the nozzle carrying portion of each of said driven chain members throughout the reciprocatory path of said nozzle.

12. The paint spray machine as defined in claim 8 and having chain support brackets fixed to said frame between said driven chain members, support arms extending outwardly from said brackets and positioned inside of each of said driven chain members, back-up runners fixed to said support arms and being engageable with the nozzle carrying portion of each of said driven chain members throughout the reciprocatory path of said nozzle, and adjustable means associated with said back-up runners for variable positioning thereof outwardly against said driven chain members.

13. The spray mechanism as defined in claim 7 and wherein said last mentioned means comprises a servomotor secured to said frame, and control means actuable by said servomotor and operatively associated with said support bar to limit pivotal movement thereof and to variably position said spray nozzle relative to said driven chain members.

14. The spray mechnism as defined in claim 7 and having timing mechanism drive means operably connected to said first idler shaft, a plurality of shafts rotatably driven by said drive means, cam means mounted on said shafts, a spray control valve, a valve control link pivotally supported on said frame adjacent said shafts, and cam follower means operatively connected to said link and actuably engaged with said cam means to disrupt the spraying operation during predetermined portions of nozzle movement.

15. The spray mechanism as defined in claim 7 and having chain support brackets fixed to said frame between said driven chain members, support arms extending outwardly from said brackets and positioned inside on each of said driven chain members, back-up runners fixed to said support arms and being engageable with the nozzle carrying portion of each of said driven chain members throughout the reciprocatory path of said nozzle, and adjustable means associated with said back-up runners for variably positioning thereof outwardly against said driven chain members.

References Cited in the file of this patent UNITED STATES PATENTS 1,966,093 Gn'flin July 10, 1934 2,728,689 Ransburg Dec. 27, 1955 2,777,419 Paasche Jan. 15', 1957 2,840,037 Verba June 24, 1958 2,910,993 Phillips Nov, 3, 1959 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,008,648 November 14 1961 William A. Brady Jr., et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 69 for "plan" read plane column 6, line 74, for "member" read members column 7 line 23 for "is" read in 3 line 32, strike out "axes" Signed and sealed this 10th day of April 1962.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

